There are many different kinds of lasers currently utilized in medical procedures. In some of these techniques the laser-tissue interaction occurs within the body, such as with the Argon laser or YAG laser for intraocular use. When this occurs, no smoke plume is produced. Other types of lasers are focused upon the outside surface of the body such as, for example, the CO.sub.2 laser which is used on skin, or the excimer laser, which is used on the surface of the cornea of the eye. When these types of lasers interact with tissue, a plume of smoke is generated which enters the air space above the tissue. This smoke plume has been shown to be composed of water vapor as well as vaporized tissue. A similar smoke plume results from electrical cauterization of body tissues.
Substances contained within the tissue are thrown into the smoke plume as a result of the laser's explosive contact with the target tissue. In the case of CO.sub.2 laser smoke, intact papillomavirus (Garden, J. M. et al. JAMA 1988,; 259:1199-1202) and intact infectious papillomavirus (Sawchuk, W. S. et at., J. Am Acad. Dermatol, 1989; 21:41-49) have been demonstrated when smoke is tested from the interaction of the CO.sub.2 laser and virally induced papillomas.
Studies have shown that the smoke generated from CO.sub.2 laser treatment of non-infected dog tongue induces a positive Ames' test for microbial mutation (Mihashi, S. et al., paper at Fourth International Society for Laser Surgery, Tokyo, November, 1981). This result indicates some level of carcinogenicity associated with such a laser generated smoke plume, even as a result of surgery on non-infected tissues.
Papillomavirus has been indicated to be a causative agent for some cervical cancers. Thus, the presence of intact papillomavirus in smoke plumes may render laser smoke from this source even more mutagenic.
Investigators such as Garden, J. M. et al. (JAMA 1988,; 259:1199-1202) who have studied the smoke plume from the CO.sub.2 laser have recommended efficient evacuation of the smoke that is produced so that the surgeon and other health care workers in the room are not exposed to any potentially infectious or carcinogenic smoke.
The United States Government Department of Labor, Occupational Safety and Health Administration (OSHA) has outlined regulations (Part II, 29 CFR Part 1910.1030, Occupational Exposure to Bloodborne Pathogens: Final Rule, Dec. 6, 1991), that require employers to keep work places safe for employees. These guidelines address the goal of avoiding reasonably anticipated occupational exposure of eyes, mouth, other mucous membrane, non-intact skin, or parenteral contact with blood or other potentially infectious materials as a result the performance of an employee's occupational duties.
Potentially infectious materials include any unfixed tissue or organ (other than intact skin) from a human (living or dead) source individual. Under circumstances in which differentiation between bodily fluid types is difficult or impossible, all body fluids are considered potentially infectious materials.
All procedures involving blood or other potentially infectious materials are required under OSHA regulations to be performed in such a manner as to minimize splashing, spraying, spattering, and generation of droplets of these substances. For example, masks in combination with eye protection devises such as goggles or glasses with solid side shields or chin length face shields must be worn whenever splashes, spray, spatter or droplets of blood or other potentially infectious materials may be generated and eye, nose, or mouth contamination can be reasonably anticipated.
Also, vacuum lines must be protected with liquid disinfectant traps and high efficiency particulate air (HEPA) filters or filters of equivalent or superior efficiency are required and must be checked routinely and maintained or replaced as necessary. Finally, OSHA requires that when there is occupational exposure, the employer shall provide, at no cost to the employee, appropriate personal protective equipment such as, but not limited to, gloves, gowns, laboratory coats, face shields or masks and eye protection, and mouthpieces, resuscitation bags, pocket masks, or other ventilation devices. Personal protective equipment must not permit blood or other potentially infectious materials to pass through to or reach the employee's work clothes, street clothes, undergarments, skin, eyes, mouth, or other mucous membranes under normal conditions of use and for the duration of time which the protective equipment will be used.
Surgeons who perform laser operations on the surface of the body routinely encounter the production of smoke commonly referred to as a "plume", from the laser's impact. As the plume of smoke can actually be smelled, it is actually making contact with the mucous membranes of the nose. It is clear that the smoke plume material would be considered potentially infectious by the above-referenced guidelines established by OSHA. Furthermore, since the plume material has been shown to be mutagenic and to transport intact infectious papillomavirus (in the case of CO.sub.2 laser, papilloma interactions), an efficient evacuation of this smoke plume, away from the patient, surgeon and other medical personnel is prudent and desirable. The absence of an efficient smoke plume evacuator for surgical lasers which generate a smoke plume appears to be in direct violation of current OSHA regulations.
The American National Standards Institute (ANSI), for Safe Use of Lasers in Health Care Facilities also publishes regulations governing the safe use of surgically induced smoke plumes (ANSI-Z 136.3-1996). In this publication, ANSI defines laser generated Airborne Contaminants (LGAC) in a similar way as OSHA and designates these surgically included smoke plumes as dangerous. These plumes are further stated to be produced by Class 4 lasers, high power Class 3b lasers, and electrosurgical devices and instrumentation. ANSI stipulates that through local exhaust ventilation, the LGAC shall be capture as near as practical to the point of production and either be completely trapped within the system or vented out of the area (see, American National Standard Fundamentals Governing the Design and Operation of Local Exhaust Systems. ANSI.
Currently there are two excimer (excited dimer) laser systems approved for use in The United States. Other excimer laser companies also have lasers that are being used in other countries. The Summit Technology, Inc. laser system sold in the United States has no provision for smoke plume evacuation at all. The VISX.TM. excimer laser system does have a unidirectional smoke plume evacuator, but the closest the evacuator orifice in this known evacuator is located, in relation to the laser treatment site, is approximately 3.8 cm, according to communications with VISX.TM. Incorporated technical support personnel.
Research has demonstrated that a laser smoke plume is approximately 98.6% efficiently evacuated when the orifice of the evacuator is 1.0 cm from the target site. The efficiency drops to approximately 50% when the evacuator orifice is moved to 2.0 cm. It is clear that an orifice that is maintained 3.8 cm from the treatment site is inadequate to produce an efficient evacuation of the laser plume. (Sawchuck, W. S. et al., Infectious Papillomavirus in the vapor of warts . . . , J. AM. Acad. Dermatol., 1989; 21: 41-49).
The above limitations in equipment presently available explain why surgeons and other health care workers consistently smell the laser smoke plume that emanates from the corneal surface when excimer laser procedures are performed with laser machines presently commercially available, for example, those sold under the VISX.TM. and SUMMIT trade names.
The present invention encompasses any evacuation device which can be placed in close proximity to the site of impact of any surgical laser or electrical cautery. The devices which fulfill this criteria must have vacuum openings which are disposed during use closer than 3.8 cm from the actual treatment site.
All embodiments of the invention herein also perform as efficient smoke evacuators while remaining out of the direct path of the incident laser light. An additional feature of this invention allows various embodiments to possess additional functional features that enhance the devices' utility, but do not impair the transmission of the incident laser light and which still enable efficient smoke plume evacuation. Embodiments are described which also enable surgical lasers to interact with tissues under different fluid mixtures.
Several practical embodiments of the new evacuator device are described hereafter. The various structures all share the common ability to efficiently evacuate the smoke plume generated from a laser impact upon human or animal tissue. For the sake of discussion, excimer laser ablation of the cornea will be utilized as an example, but it is to be understood that the new device is also applicable to any other surgical procedure, such as cauterization in the usual manner, that produces a smoke plume that enters the atmosphere above (exterior of and adjacent to) the surgical treatment site.
Thus, although the term "laser" is used throughout this document, it is to be understood that in most cases the procedure under discussion could also be other types of procedures, particularly surgical procedures, which cause the production of smoke. Thus the specification and claims are not to be interpreted as limited strictly to laser surgical procedures.
The new devices disclosed herein are preferably disposed with vacuum apertures closer to the treatment site than 3.8 cm. Ideally, the apertures should be as close as possible to the treatment site while not impairing the function of the laser. While the new evacuators will function at a distance greater than 3.8 cm, closer placement is necessarily preferred for optimal smoke removal. Such closer placement is not possible with evacuators known in the art. Precisely how much closer the new device may be positioned will depend on a number of factors, including, for example, the type of surgery being performed and the skill of the particular surgeon, as well as the area of the body upon which laser treatment is imposed.
In addition to being closer than 3.8 cm, it is preferred to evacuate the smoke plume from more than one aperture to increase efficiency and to draw the laser smoke away from the treatment site in a fashion that does not draw the smoke over one part of the corneal surface more than over another part.
If an evacuation device with only a single aperture is used, as repeated laser pulses strike the corneal surface, smoke being evacuated will cross the cornea in only one direction, i.e., from one side of the eye under treatment to the opposite side thereof; i.e. smoke is drawn in an uneven distribution across the surgical site and physically interferes with the fluence of the laser light upon the cornea, such that an area with greater smoke concentration will receive less laser light because the smoke itself absorbs some of the laser energy.
By using the new evacuator with numerous apertures circumferentially located around the cornea, laser generated smoke is drawn directly toward the closest aperture and not across the cornea. In other words, the smoke is drawn radially outwardly from the inner portion (approximate center) of the surgical site, within a hypothetical perimeter established by the evacuator body portion of the device. This technique will improve reliability of the excimer laser and provide a more predictable surgical outcome by preventing smoke from crossing the path of the laser.
A commercially available aspirating speculum is available and referred to as the McBratney aspirating speculum, shown on page 248 of the Storz.RTM. Ophthalmic Instruments catalog at number E4117. This device has suction tubes connected to both arms of an eyelid speculum. However, the arrangement of apertures makes the device unsuitable for the present purpose of smoke plume removal. Rather, the McBratney speculum is structurally designed for removal of fluids from the surface of the eyeball during surgery. The holes are positioned inside the upper bend, to the left and right of center on the ends of the rigid 21 gauge metal tubing of which the speculum is made, two holes per arm. The McBratney speculum holes are filed to a size of 0.016 inches, much smaller than is necessary to accomplish the present purpose of efficient smoke plume removal.
Excimer laser companies have attempted blowing clean nitrogen gas across the cornea during excimer laser corneal treatments. The theory behind this was that by blowing nitrogen across the cornea, the laser generated smoke would be removed from the pathway of the incident light and thereby create improved uniformity in the fluence of the laser light upon the cornea. The use of nitrogen blowing was abandoned when the clinical outcomes were determined to be less desirable than when no Nitrogen blowing was utilized.
One possible reason for this decrease in the quality of the clinical outcomes may be explained by the fact that the nitrogen was blown in only one direction, entirely across the cornea, as opposed to being introduced evenly and circumferentially as is possible with some of the embodiments described herein.
As explained hereafter, another potential cause for past problems with nitrogen blowing may be due to the facts that nitrogen is an intrinsically inert gas and that the atmosphere contains approximately 21% oxygen. Interaction of an excimer laser with the cornea produces a photochemical disruption of the molecules comprising the cornea. It is not clear what changing the partial pressure of the gases in the atmosphere would have upon the nature of this photochemical reaction, but considering that oxygen is a reactive molecule and that the excimer laser impact has been demonstrated to be an explosive phenomenon (Puliafito, C. A., et al., Arch Ophthalmol. 1987; 105:1255-1259), control over the concentration of potentially reactive gases in the air space above the laser impact site is considered to be important to obtaining predictable, reliable results with any laser surgery, e.g. excimer laser surgery.
With the present invention, the vacuum produced by the smoke plume evacuator can be configured to efficiently remove the generated laser smoke in exchange for clean room air, leaving the partial pressure of the air mixture above the treatment site unchanged. Furthermore, another embodiment of this invention allows for simultaneous evacuation of the laser plume and circumferential delivery of any clean fluid mixture into the laser path which may be more desirable for laser-tissue interaction (for example, a reactive atmosphere containing a partial pressure of oxygen of 25% as opposed to 21%).
During excimer laser corneal surgery, it is customary to place an eyelid speculum into the cul-de-sacs (engaging and/or under the lids) of the eye. This is done so that the patient cannot blink during the treatment process. In one embodiment of this invention, a lid speculum is configured with an integral smoke plume evacuator so that this device addresses a need that already exists in standard excimer laser surgery. Other embodiments are disclosed herein which serve multiple purposes but which alter the already somewhat established protocol for excimer laser treatments.
In some embodiments of this invention, a lid speculum is configured with a smoke plume evacuator so that the new device can simultaneously keep the eyelids open while efficiently removing the laser smoke plume. The apertures of this lid speculum are preferably disposed in normal use position less than one centimeter from the treatment site and as such can be optimally efficient in removing the laser smoke plume.
Because a lid speculum is a standard device utilized for excimer laser surgery, this device will perform two functions at the same time. The evacuated smoke plume can be routed into the standard filtration system that is present on the VISX.TM. Star Excimer Laser System.TM., or routed to a standard commercially available evacuation system with appropriately replaceable filtration systems. The nature of the commercially available filtration system is well known.
Finally, for the lid speculum design, one embodiment would contain an additional set of tubing that would be stacked upon the plume evacuator tubing. This additional set of tubing can be used to bring in clean gas or other fluids or mixtures thereof which are different from atmospheric (ambient) gas. This process enables the laser to interact with tissue under a fluid environment which is different from atmospheric gas and which may allow for an improved laser-tissue interaction.
Another embodiment of this invention is an ocular fixation device which comes in contact with the conjunctiva around the cornea. One design that is considered is similar to the Fine-Thornton fixation ring as sold by Rhein Medical, Inc. This device has a handle suitable for manually controlling the device. The portion which contacts the patient's eye is an incomplete circle with small teeth to engage the conjunctival surface. In this embodiment, the portion of the fixation ring just above the part that contacts the conjunctiva can be a tube with one or more apertures, which tube leads to a filtration vacuum system which is appropriate for receipt of biohazardous materials for disposal thereof.
In use, this embodiment of the new device is placed against the conjunctiva around the cornea to assist in the fixation of the eye for surgery, and the vacuum, when activated, enables efficient smoke plume evacuation preferably at a distance approximately 1.0 cm or less. With the fixation ring embodiment, an additional circle of tubing can be attached to the fixation device so that different gas mixtures can be delivered to the treatment site and enable potential modifications of the laser-tissue interaction.
Other embodiments of this invention are conceived whereby a structure with one or more apertures is placed against the eyelid skin hovering over the cornea. With this embodiment, a standard eyelid speculum could be utilized. This tubing, with one or more apertures, could have small vertical extensions which then contact the skin and enable the surgeon to hold this in place in close proximity to the treatment site. This device will have a greater distance from the treatment site than either the lid speculum embodiment or the fixation ring embodiment but will still provide a level of smoke plume evacuation efficiency which is greater than that which is currently available in the VISX.TM., Incorporated or Summit Technology, Inc. lasers. This embodiment can also incorporate a separate ring of tubing which can introduce different gas mixtures to the space above the treatment site.
One of the ways in which the fixation embodiment of the device disclosed herein is useful is for surgery on other body surfaces, when those surfaces are receiving various laser treatments. One example of this is the laser removal of virally produced condyloma of the genital tract. In this fashion, the condyloma to be treated are located within the circular fixation ring which holds the skin taut, while the laser treatment is delivered efficiently through the central aperture of the fixation ring. Also during this treatment, the smoke that is generated is efficiently removed because of the very short distance between the laser tissue interaction site and the apertures of the smoke evacuation system.
Another site for potential use is the cervix. Collins has described a vaginal speculum which is partly connected to a vacuum suction device. The intention of that device is to remove smoke from the vaginal vault during cervical laser treatments or other smoke producing procedures. The Collins patent does not teach any important distances from the source of the smoke, and as such the embodiments described in that patent do not provide for an efficient smoke removal system, as does the present devices.
In the present invention, a standard vaginal speculum is inserted and a long handled fixation device connected with tubing inserted into the vagina with the circular fixation ring being brought against the uterine cervix to hold it steady, to manipulate it during treatment, and, most importantly, to evacuate any smoke generated from this tissue during laser or other smoke producing procedures. This function for the fixation device is better than the Collins device in that improved visualization and more efficient smoke evacuation can occur because of the greatly shortened distance between the laser tissue interaction and the apertures of the smoke evacuation tubing.
The embodiment for cervical treatment is therefore ordinarily expected to have a longer fixation handle than that used upon the eye, and the distal fixation ring would have to be of larger diameter than that used on the eye. A reasonable useful range of diameters is considered, for example, a 2.5 to 3.0 cm diameter ring-shaped evacuator body is appropriate for treatment of the uterine cervix. Similarly, any other surface or body cavity which requires an efficient evacuation of smoke from the interaction of laser or other cautery devices with tissue could be utilized with appropriate modification of the speculum, fixation device or smoke evacuation tube of the new evacuation device.
As mentioned elsewhere herein, an independent, but connected tubing can be arranged such that one set of tubing is used for efficient close range smoke evacuation, while the other is used for the importation of any desired air/gas mixture, or liquid (fluids). If liquid is introduced through the second set of tubing, the vacuum present on the second set of tubing can double as a liquid evacuator as well. If the fixation device is used in the vagina, other baffles or structures can be affixed to the fixation handles, as may be necessary to assist in keeping vaginal tissues out of the direct path of the laser.
Although possibly unnecessary, the present device is considered a conduit for these procedures, such that even a conventional light pipe could be introduced down the handle to facilitate the view of the cervix for appropriate treatment with the laser.
Accordingly, it is among the many goals and advantages of the present invention to provide a surgical smoke plume evacuation device which may be integral with or detachably connected to a speculum for use in surgical treatment of tissue with a laser, electrical cautery or other smoke plume causing device. Various embodiments of the new device are appropriate for different tissues, at different areas of the body and can be used with a variety of types of speculums.
It is further among the many goals and advantages of the device having the features enumerated above, that it can be made of materials that are relatively inexpensive and disposable, or alternatively may be sterilizable for reuse and may be adapted for introduction of fluids into the area ambient to the surgical site.
It is still further among the many goals of the invention to provide a device which can be used by an already skilled professional in the art with little or no additional training or practice prior to use on a patient, which device will protect the surgeon, the patient and other individuals in the vicinity of a surgical procedure from any potentially hazardous substances that may be in a smoke plume produced during the procedure, and that such device will thereby assist medical facilities in meeting OSHA and ANSI standards for safety in work places using laser surgical procedures.
Accordingly, in furtherance of the above goals, the present invention is, briefly, a surgical laser smoke plume evacuator which includes an evacuator body formed to a shape which is suitable for placement in normal use position substantially entirely around and adjacent to a tissue site upon which laser surgery is to be performed. The evacuator body has structure for removing smoke therethrough, and a smoke exit portion in communication with and extending from the evacuator body. The smoke exit portion is connectable to vacuum source, to thereby apply a vacuum to the evacuator body and cause smoke which is created at a surgical site during surgery to be removed from the surgical site through the evacuator body and the smoke exit portion.
The invention is also, briefly, the combination of an eyelid speculum and a surgical laser smoke plume evacuator device, wherein the smoke plume evacuator device includes an evacuator body which is formed to a shape which is suitable for placement in normal use position substantially entirely around and adjacent to a tissue site upon which laser or other smoke producing surgery is to be performed. The evacuator body has structure for removing smoke therethrough. A smoke exit portion is in communication with the evacuator body, and extending away from the evacuator body, the smoke exit portion is connectable to vacuum source, to thereby apply a vacuum to the evacuator body and cause smoke which is created at a surgical site during surgery to be removed from the surgical site through the evacuator body and the smoke exit portion.
Further in the combination, the evacuator body of the smoke plume evacuator device is formed of tubing and the structure for removing smoke therethrough is a plurality of openings spaced around an internal aspect of the evacuator body and extending from a luminal surface of an internal aspect thereof to a nonluminal surface thereof, at least some of the plurality of openings being disposed less than 3.8 cm from a point of smoke producing surgical contact with tissue of the surgical site.
The invention is further, briefly, a method of removing a smoke plume created during surgery. The new method includes selecting a smoke plume evacuator device having an evacuator body and a smoke exit portion in communication with the evacuator body, positioning the evacuator body of the surgical smoke evacuation device around a surgical site so that the site is accessible via an inner aspect of the evacuator body, and so that at least some structure on the evacuator body inner aspect for removing smoke are disposed less than 3.8 cm from the smoke producing surgical treatment site, connecting the smoke exit portion of the evacuation device to a vacuum source, applying a vacuum to the smoke exit portion of the evacuation device, and initiating a smoke producing surgical procedure upon tissue at the surgical site, the smoke being produced exiting radially away from the surgical site via the structure for removing smoke on the evacuator body and then via the smoke exit portion toward the vacuum source.
These and other advantages and features of the invention will be in part apparent and in part pointed out hereinbelow.